"I was 20 pounds heavier and wanted to look like those girls with fantastically beautiful bodies like Jennifer Aniston or Jessica Alba, but I just couldn't lose the weight," Heigl admits to the mag. But she's OK with that!

"It's only now that I realize how hard those girls work for their bodies, and what level of commitment they make to do that," she says. The yoga, personal training sessions and painstakingly planned meals that make Aniston and Alba's bods world-famous just aren't for her, she explains. "I'm too lazy, and I like food and I like my free time too much to spend it working out!"

Married to musician Josh Kelley for four years -- they share daughter Naleigh, 2 -- Heigl also confides to the mag she's not sure how she'd react if her man had an affair.

"I've been debating this lately. Josh and I always said that cheating would be a deal breaker; there is no second chance. But I've seen friends and acquaintances go through it and they’ve found a way back to the relationship, and a way to forgive each other," says Heigl, whose "New Year's Eve" co-star Berry famously dealt with cheating. "And as much as I would kill him if he cheated because it would destroy me, I have started to question whether, if a mistake were to be made and it was a one-time thing, I would forgive him."